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Clinical and molecular features of methicillin-resistant,coagulase-negative staphylococci of pets and horses

Kern, Andrea ; Perreten, Vincent

In: Journal of Antimicrobial Chemotherapy, 2013, vol. 68, no. 6, p. 1256-1266

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    Title
    • Clinical and molecular features of methicillin-resistant,coagulase-negative staphylococci of pets and horses
    Author
    • Kern, Andrea. Institute of Veterinary Bacteriology, Vetsuisse Faculty, University of Bern, Bern, Switzerland
    • Perreten, Vincent. E-mail: vincent.perreten@vetsuisse.unibe.ch
    Document Type
    • Postprint
    Language
    • English
    Published in
    • Journal of Antimicrobial Chemotherapy, 2013, vol. 68, no. 6, p. 1256-1266. Oxford University Press
    Other Version
    OAI-PMH Identifier
    • oai:doc.rero.ch:301563
    Summary
    Objectives To determine the antibiotic resistance and fingerprint profiles of methicillin-resistant coagulase-negative staphylococci (MRCoNS) from animal infections among different practices and examine the history of antibiotic treatment. Methods Isolates were identified by mass spectrometry and tested for antimicrobial resistance by broth dilution, microarrays and sequence analysis of the topoisomerases. Diversity was assessed by PFGE, icaA PCR and staphylococcal cassette chromosome mec (SCCmec), arginine catabolic mobile element (ACME) and multilocus sequence typing. Clinical records were examined retrospectively. Results MRCoNS were identified as Staphylococcus epidermidis (n = 20), Staphylococcus haemolyticus (n = 17), Staphylococcus hominis (n = 3), Staphylococcus capitis (n = 1), Staphylococcus cohnii (n = 1) and Staphylococcus warneri (n = 1). PFGE identified one clonal lineage in S. hominis isolates and several in S. haemolyticus and S. epidermidis. Fourteen sequence types were identified in S. epidermidis, with sequence type 2 (ST2) and ST5 being predominant. Ten isolates contained SCCmec IV, seven contained SCCmec V and the others were non-typeable. ACMEs were detected in 11 S. epidermidis isolates. One S. hominis and 10 S. epidermidis isolates were icaA positive. In addition to mecA-mediated β-lactam resistance, the most frequent resistance was to gentamicin/kanamycin [aac(6′)-Ie-aph(2′)-Ia, aph(3′)-III] (n = 34), macrolides/lincosamides [erm(C), erm(A), msr, lnu(A)] (n = 31), tetracycline [tet(K)] (n = 22), streptomycin [str, ant(6)-Ia] (n = 20), trimethoprim [dfr(A), dfr(G)] (n = 17), sulfamethoxazole (n = 34) and fluoroquinolones [amino acid substitutions in GyrA and GrlA] (n = 30). Clinical data suggest selection through multiple antibiotic courses and emphasize the importance of accurate diagnosis and antibiograms. Conclusions MRCoNS from animal infection sites are genetically heterogeneous multidrug-resistant strains that represent a new challenge in the prevention and therapy of infections in veterinary clinics